Volume 5, Issue 7 (2025) – 20 articles
Cover Picture: The poor rate performance of hard carbon (HC) in carbonate electrolytes limits its applicability in hybrid capacitors, primarily due to the low working potential and the slow Na+ transport kinetics within the potential plateau region. The slow desolvation of Na+ at the electrode surface and sluggish transport of Na+ through the solid electrolyte interface are the critical factors contributing to this issue. In this study, Co3O4 nanoparticles are uniformly self-grown on the HC surface to modulate the surface chemistry of HC. The introduction of Co3O4 not only facilitates the desolvation of Na+ and reduces internal resistance, but also provides additional active sites for Na+ storage as an active material. As a result of these dual effects, HC125@Co3O4 (a composite with an optimalCo3O4 loading on HC surfaces) exhibits superior rate performance and reversible capacity compared to pure HC. The sodium-ion hybrid capacitor assembled with the HC125@Co3O4 anode and activated carbon cathode demonstrates high energy density (129.5 Wh kg-1 at 583 W kg-1) and high power density (26.5 Wh kg-1 at11,650 W kg-1), along with excellent long-time cycling stability. This study offers an effective solution to the poor rate performance and slow kinetics of HC in carbonate-based electrolytes, addressing the issue from the perspective of the electrode-electrolyte interface.
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Cover Picture: Seawater electrolysis offers a sustainable solution for hydrogen production by utilizing ocean water as an electrolyte. However, the chlorine evolution reaction (ClER) and the accumulation of magnesium and calcium precipitates pose significant challenges to efficiency and durability. ClER competes with the oxygen evolution reaction, reducing hydrogen output and accelerating electrode degradation, while precipitate formation on the cathode blocks catalytic sites and impairs long-term performance. Anion exchange membrane water electrolyzers tackle these challenges by leveraging alkaline media to suppress ClER and enhance catalyst stability. Recent advances in selective catalysts, protective coatings, and alternative oxidation reactions further improve reaction selectivity and energy efficiency. Additionally, strategies such as surface engineering and pH modulation mitigate precipitate formation, ensuring stable operation. Scaling these innovations into anion exchange membrane water electrolyzer systems demonstrates their potential for industrial-level hydrogen production. By overcoming fundamental challenges and practical barriers, seawater electrolysis advances toward commercial deployment and a sustainable energy future.
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